It just needs a healthy BMI with a 0.75 ~ish Waist:Hip ratio and normal head and limb proportions. As well as available in a range of skin tones and a variety of hair colours.
Unfortunately, Barbie appears to be impossible to get rid of. We tried to ban “her” in our house, but our daughter managed to obtain two from friends with large collections. It’s like trying to stop boys from playing with toy guns (tried that too) — ultimately futile as they get hold of them anyway.